B Gravitational effects of a small black hole passing your body

[fresh_42]

TL;DR

I have no idea how serious this is, but it sure sounds funny. Someone calculated it! I think the paper is worth more than its clickbait title.

Abstract​

The gravitational effects of a Primordial Black Hole (PBH) passing through the human body are examined, with the goal of determining the minimum mass necessary to produce significant injury or death. Two effects are examined: The damage caused by a shock wave propagating outward from the black hole trajectory, and the dissociation of brain cells from tidal forces produced by the black hole on its passage through the human body. It is found that the former is the dominant effect, with a cutoff mass for serious injury or death of approximately $MPBH \gt> 1.4\cdot 10^{17}\,g.$ The number density of primordial black holes with a mass above this cutoff is far too small to produce any observable effects on the human population.

Source: https://www.worldscientific.com/doi/10.1142/S0218271825410032

 

[.Scott]

I read through the article.
This is their conclusion (in part):

Intriguingly, the smallest PBH mass that can lead to significant human injury (Eq. (3)) lies near the lower bound on PBH dark matter in Eq. (1), raising the possibility that the absence of such events could provide an additional constraint on the PBH abundance, as in the case of MACHO dark matter.

I do not agree. I do not believe their method of incidental detection of Primordial Black Holes is as effective as they presume. If every year, one millionth of the population was struck down by a PBH, this would likely go unnoticed. The tissue damage would be the result of a shock wave, and although it may be as damaging as a small caliber bullet, externally, it would not be very bloody. In most cases, it would be passed off as a stroke. If an autopsy was performed, trauma would be indicated, but it would have to be a very unusual autopsy for the full pattern left behind by a black hole to be recognized.